1. Field of the Invention
The present invention relates to a pressure sensor device and, particularly, to the attachment structure of a sensor module having a sensor element to a case.
2. Description of the Prior Art
FIG. 18 is a sectional view of a pressure sensor device of the prior art disclosed by Japanese Laid-open Patent Application No. 9-43076.
In FIG. 18, a pressure sensitive element 2 is placed in a resin case 1 and a pressure medium is introduced to the rear side of the heat sensitive element 2 from the measurement pressure introduction pipe 3 of the case 1. The case is integrated with a connector unit and molded by inserting a terminal 4 therein. The terminal 4 and the pressure sensitive element 2 are electrically connected to each other by a wire 5.
Since the semiconductor pressure sensor device of the prior art is constituted as described above and the pressure sensitive element 2 is fixed in the case which is an exterior constituent part, it is difficult to measure pressure and the characteristic properties of this pressure sensor device cannot be adjusted before the pressure sensitive element 2 is placed in the case and wired. Since the pressure element 2 is set in a recess portion of the case 2 and connected to the terminal 4 by the wire 5, only the rear side of the pressure sensitive element 2 receives pressure, thereby making it impossible to use the case for a pressure sensitive element which receives pressure on the front side.
It is an object of the present invention which has been made to solve the above problem to obtain a pressure sensor device having high reliability and excellent workability, which can be used for both types of sensor elements which receive pressure on the front side and the rear side, can be reduced in size, whose characteristic properties can be checked before a sensor module is set in the case, and which eliminates the need for changing the internal structure of the case when the outer shape of the case or the shape of a connector is altered.
According to a first aspect of the present invention, there is provided a pressure sensor device in which a wall portion projecting to surround a sensor element is formed on the surface of a sensor module, a groove potion is formed in an upper case or a lower case at a position corresponding to the wall portion, and an end of the wall portion is mated with this groove portion through an adhesive to form a closed space for storing the sensor element.
According to a second aspect of the present invention, there is provided a pressure sensor device in which the wall portion is formed on the surface of one side opposed to either one of the lower case and the upper case of the sensor module.
According to a third aspect of the present invention, there is provided a pressure sensor device in which the wall portion is formed on the top and under surfaces opposed to the lower case and the upper case of the sensor module and a groove potion is formed in both the upper case and the lower case.
According to a fourth aspect of the present invention, there is provided a pressure sensor device in which a wall portion for surrounding other electronic parts such as a signal processing unit is formed on the surface of the sensor module and an end surface of the wall portion is contacted to the surface of the upper case or the lower case to form a closed space for storing the electronic parts.
According to a fifth aspect of the present invention, there is provided a pressure sensor device in which the length of the wall portion surrounding the electronic parts is lengthened, a groove portion is formed in the upper case or the lower case at a position corresponding to this wall potion, and the wall portion is mated with the groove portion through an adhesive.
According to a sixth aspect of the present invention, there is provided a pressure sensor device in which a closed space for storing the electronic parts and a closed space for storing the sensor element are located on opposite sides of the sensor module.
According to a seventh aspect of the present invention, there is provided a pressure sensor device in which a closed space for storing the electronic parts and a closed space for storing the sensor element are located on opposite sides of the sensor module at positions corresponding to each other.
According to an eighth aspect of the present invention, there is provided a pressure sensor device in which the sensor module is made from a synthetic resin and lead frames for leading the signal of the sensor element to the outside are integrated with the sensor module in such a manner that they extend through the wall portion.
According to a ninth aspect of the present invention, there is provided a pressure sensor device in which a through hole for connecting a pressure hole with a closed space for storing the sensor element is formed in the sensor module when the sensor element and a wall portion surrounding this are provided on the upper case side of the sensor module and the pressure hole for introducing a pressure medium is formed in the lower case.
According to a tenth aspect of the present invention, there is provided a pressure sensor device in which the sensor element is placed on the top surface of the sensor module through a pedestal and an introduction passage is formed in the pedestal at a position corresponding to the through hole.
According to an eleventh aspect of the present invention, there is provided a pressure sensor device in which the sensor element is placed on the top surface of the sensor module through a pedestal and the pedestal is shifted to a position not corresponding to the through hole.
According to a twelfth aspect of the present invention, there is provided a pressure sensor device in which a differential pressure through hole is formed in the sensor module at a position not corresponding to the pedestal and connected with a differential pressure introduction hole for introducing a pressure medium from the outside so that a medium pressure from the differential pressure introduction hole and a medium pressure from the pressure hole are received by the top and under surfaces of the sensor element supported by the pedestal.
According to a thirteenth aspect of the present inventor, there is provided a pressure sensor device in which a filter for purification is installed at the outlet or inlet of the differential pressure through hole.
According to a fourteenth aspect of the present invention, there is provided a pressure sensor device in which distal end portions of a plurality of lead frames are separated from other portions to form external connection portions and the lead frames can be selectively connected to the external connection portions.
According to a fifteenth aspect of the present invention, there is provided a pressure sensor device in which a bent portion is formed at an intermediate portion of each of the lead frames.
The above and other objects, features and advantages of the invention will become more apparent from the following description when taken in conjunction with the accompanying drawings.